Electric cooker



June 3 1941- G. w. wATsoN 2,243,993

' ELECTRIC cooKz-:R

Filed Dec. 5. 1938 2 Sheets-SheetI 1 I INVENTOR. G/erz/v )f/son ORNEY'June 3, 1941. G, w WATSON 2,243,993

ELECTRI C COOKER Filed Dec. 5', 1938 2 Sheets-Sheet 2 fag/z VENTOR.

A TTORNEY.

Patented June 3, 1941 ELECTRIC COOKER Glenn W. Watson, Detroit, Mich.,assigner to Penweld Oorporation, Detroit, Mich., a corporation ofMichigan Application December 5, 1938, Serial No. 243,923

4Claims.

The present invention pertains to novel apparatus for the preparation offood by the use of electric currents passed therethrough and over thesurfaces, and ride in various improvements and simplifications of thedevices shown in my copending application Serial No. 217,941', med July7, i938, now Patent No. 2,200,406, and in the co-pending application ofGlenn W. Watson and Earl C. Brannas, Serial No. 213,197, flied June il.1938, now Patent No. 2,200,405. Some of these applications disclosemeans whereby the food is subjected to current in four directions.namely, two currents through the food in opposite directions. and acurrent on each of the two principal surfaces forbrowning. I havepreviously used two different types of conductors in this operation.namely, a conductor of comparatively low resistance for the currents tobe passed through the food, and a heat-radiant conductor for browningthe surfaces by radiation as well as by the currents thereby caused toflow on the surfaces of the food.

One of the improvements introduced by the present invention resides inthe use of only one type of conducting material for performing all thefunctions named above. The conducting elements are nevertheless arrangedand connected to provide the four currents previously referred to. Theconducting material here employed is one that radiates heat when currentis passed therethrough. and may consist, for example, of conventionaltoaster wire, Globar metal. iron, tin, suitable alloys, and in fact anymaterial having the property of radiating heat when sub- Jected to theparticular current for which the apparatus is designed. Further. thismaterial is preferably sheathed in -tin or a similar conducting materialthat does not deteriorate by constant contact with the food undercooking temperature. The elements thus constituted are grouped in theapparatus in a manner to engage opposite surfaces of the food and are soconnected electrically in the circuit as to perform the two functions ofpermitting current to pass through the food for cooking the interior andof browning the surfaces by heat radiation as well as by surfacecunents.

Another object `of the invention is to connec the elements in thecircuit in such a manner that the current is uniformly distributedthroughout their entire length rather than concentrated in only a partof the length.

Still another object is to provide a checkered effect in the brownedsurfaces. In this respect, the apparatus-includes two sections forengaging opposite surfaces of the food. Each element is provided with anumber of elongated and parallel elements, the elements in one sectionbeing perpendicular to those in the other. The initial browning istherefore in the form of straight and parallel lines on each surface,those on one surface being perpendicular to those on the other. The foodis turned over after having been given a preliminary treatment, and inthis manner perpendicular lines orv a checkered effect are formed oneach surface.

Another characteristic of the apparatus is that the food under treatmentconstitutes an automatic switch controlling the flow of current. Thevalious circuits include the food itself in the current pass. I haveobserved that the current ceases to flow after a certain period oftreatment of the food, from which it must be concluded that the foodbecomes non-conducting at the end of this interval. This may possibly beexplained on the theory that the food loses much of its moisture contentduring this period, or at least is so changed in its properties that itis no longer a good conductor. However, I have aiso observed that theflow of current through the food may be resumed if the direction orpolarity is reversed. In this connection, another object of theinvention is to provide an automatic pole changer that reverses thedirection of the current and permits another flow of current after thefirst flow has ceased.

Still another object of the invention is to provide apparatus whereinthe food is propelled between opposed series of elements and cooked bythese elements. As far as I am aware, I am the rst to cook food byconveying it through an apparatus of this character.

The invention is fully disclosed by way of example in the followingdescription and the accompanying drawings, in which:

Figure 1 is a front elevation of the apparatus, with the lid raised;

Figure 2 is an end view thereof;

Figure 3 is a plan section on the line 3 3 of Figure 1;

Figure 4 is a cross section of the lid on the line 4 4 of Figure l; y

Figure 5 is a bottom plan section on the line 5 5 of Figure l;

Figure 6 is a section on the line 6 6 of Figure 5;

Figures 7 and 8 are detail perspective views illustrating the formationof the elements;

Figures 9 and 10 are similar views pertaining to amodifled form ofelement;

Figure'li is a wiring diagram;

Figure 12 is an elevation, partly in section, of a modified form ofapparatus through which the food is propelled, and

Figure 13 is a similar view of a modiiication of this type of apparatus.

Reference to these views will now be made by use of like characters thatare employed to designate corresponding parts throughout.

In Figures 1 and 2 the apparatus is shown as comprising a base section Ihaving a lid 2 attached by means of a variable hinge 3 permittingVariation in the elevation of the lid 2 in its lowered position. The topof the base I and the bottom of the lid 2 carry electrical units,described in detail below, for conducting current to the food anddistributing it in several paths, as will appear more fully hereinafter.A trough 4 is formed around the lower unit and is inclined downwardlyand forwardly, as shown in Figure 2, and discharges into a spout 5through which the juices emitted from the food during cooking areconveyed to a suitable receptacle 6 mounted on the forward wall of thebase I.

The electrical units are made up of elements of the character shown inFigures 7-10. The construction shown in Figures 7 and 8 includes a fiatstrip 1 of a material adapted to conduct current and to radiate heatwhen subjected to the current for which the apparatus is designed. Anymaterial having these properties may be employed. Examples thereof areconventional toaster wire, Globar metal, iron, tin, and various alloys.It has been found that at least some of these materials deteriorate byconstant contact with the food under the cooking temperature, and toobviate this difficulty I enclose each strip in a sheath 8 of a moredurable conducting material such as tin. The sheath is initially in theform of U or V, as in Figure '7 and the ends thereof iirmly clampedtogether as at 5 in Figure 8. It will be understood that theseoperations may be performed very rapidly and inexpensively by suitableautomatic machinery.

In a modification of the element, the inner conducting and radiatingmaterial is in the form of a wire III and is sheathed in a tube IIhaving the properties of the sheath 8. The tube is then rolled at as inFigure 10. In most cases, the ends of the inner member are exposed, fora purpose that will presently be described, and the'sheath is pressedfluid tight around the portion it surrounds.

Each of the units previously mentioned includes a panel I2 of suitableinsulating and supporting material of such size as or the lid, as thecase may be. The elements are inserted therein to form series ofparallel lines, the base being formed with lined slots I3 to receive theends of adjacent elements. It will be seen by reference to Figures 1 and3 that the slots of alternate lines form parallel rows, each such rowbeing distinct or spaced from the others and no two rows coinciding. Inother words, the

'slots or joints of alternate lines of element are staggered withrespect to the joints or slots oi" the intermediate elements.

For the purpose of clarity in description, the two sides of the circuitwill be designated as A and B. Alternate lines A of elements areconnected to the side A, and the intermediate lines B are connected tothe side B. To effect this arrangement, the various elements are turneddown into the slots I3, the bare ends previously mentioned being exposedat the rear or concealed to be fitted in the base v surface of the panelI2. At the exposed surfaces of the panels, the elements are fullysheathed. The slots I3 are also sealed by solder dropped therein whichalso joins the bare ends of alined elements.

Bus bars I5 lying transversely of the elements are connected to thejoined ends of series A, which joined ends are allned as previously setforth. These bars are connected at one end to the A side of the circuit.Similarly, another set of bus bars I6 perpendicular to the lines ofelements is connected to the alined joined ends of the B series; andthese bars are each connected at one end to the B side of the circuit.

The inwardly protruding or adept ends of the` two series of elements arepreferably at dierent levels, as shown in Figure 6, to avoidinterference of the bus bars with each other and to facilitate assembly.The lines of elements of each unit are perpendicular or at a differentangle to those of the other unit, although the lines in a given unit areparallel to each other and interconnected in like manner by bus bars andalternately to opposite sides of the circuit. This relation isillustrated in Figures 1 and 3 and also diagrammatically in Figure 1l.

In the operation of the device as thus far described, let it be assumedthat current of proper voltage is applied to the circuit. The variousaccessories in the circuit will subsequently `be described. It will beevident by examination of the Figure 11 that there is no means ofconveying current between elements of the same unit or opposite units,so that there is no closed circuit unless such means is provided.

The food to be prepared is laid on the base element, and the upperelement is brought down upon the food, and the current started through asuitable switch. The food then becomes a conductor between elements Aand B on each surface of the food as well as between elements A and B atopposite surfaces. Four paths of current are thereby provided, namely, acurrent on each surface and two currents in opposite directions throughthe food, as fully explained in my copending application.

The surface currents brown the food, and the currents flowing throughthe food cook the interior thereof. The electrical conductivity of thefood is due to certain properties. In meats, for example, it is theliquid and mineral content. I have observed that these propertiesdisappear as the food undergoes treatment, and with the disappearance ofthese properties the current ceases to now in any direction, moreover,in the case of many foods, the food becomes non-conductive when it hasbeen cooked to a sufficient degree for edibility.

I have also observed that the flow of current may be resumed if itsdirection or polarity is reversed. Accordingly, I provide an automaticpole changer that operates on the stoppage oi current in the firstinstance. This device comprises a solenoid 20 in series with the circuitand having an armature 2| normally withdrawn from the core 22 by aspring 23. A pair of spaced contacts 24 and 25 are provided in the Bside of the circuit, and between them is a single contact 26 in the Aside.

A pair of iingers 21 and 28 are pivotally mounted, and insulated from acommon support 29 and are adapted to engage the intermediate contact 26and either one of the remaining contacts 24 and 25. The iingers areconnected respectively to the A and B sides of the circuit.

The common support 2l is joined by a link 3l to the amature 2 I Whenthere is no current flowing, or when the apparatus is idle, the spring23 withdraws the solenoid 2i and brings the fingers 21 and 28 intoengagement with the contacts 26 and 24, as illustrated in Figure l1.closed through the manual switch 3| and through the food as previouslyset forth, the magnet is energized, the armature attracted, and thefingers V`swung into engagement with contacts. and 28.

When currentceases to flow through the food by the vanishing of theconductive properties of the latter, thearmature is again withdrawn bythe spring 23, and the polarity or direction of current therebyreversed. Under these conditions current again flows through the foodand although it also ilows through the solenoid, it has desired.

The circuit may also contain a pilot light I4, a visible ammeter 35 anda time switch 36 for speciilcally controlled operation. The operatingcurrent is preferably supplied through a transformer 31 that alters theline voltage according to the requirements of the apparatus.

Figures l2 and 13 illustrate apparatus through which the food ispropelled in cooking. In Figure 12 is illustrated a rigid frame 40 inwhich are `iournaled rollers 4i geared together at their ends at 42.Adjacent thereto is a resiliently mounted frame 43 carrying similarrollers 44 also geared to one another but normally spaced from therollers 4I a sumcient distance to receive the food. The bodies of therollers consist of conducting and heat-radiating properties as describedabove and are connected in the manner already described to furnish fourcurrents through and on the surfaces of the food. A motor 45 is gearedto a roller of one of the groups to drive that group and is connected bya flexible cable 46 to a roller of the other group.

In the construction shown in Figure 13, there are two spaced unitssimilar to the units shown in Figure 1l. The elements 41 of the units 4Iand 49 are, however, parallel to one another and transverse to thedirection in which the food is moved. Thus, the food is browned over theentire extent of both surfaces rather than along parallel lines as wouldbe the case if the elements were parallel to the line of movement. Oneof the units is preferably rigid and the other resiliently mounted onsprings 50. A hook 5I is and is fastened to a cable 52 wound on a pulley53 which is geared to a motor 64. A suitable switch 55 in the circuitgoverns the flow of current.

Referring again to the principal construction illustrateddiagrammatically in Figure 1l, it will be noted that the elements,because of their heatradiating property, brown the surfaces of the foodby radiation, and at the same time deliver the two surface currents andthe two currents through the food in the manner described. Par- As soonas the circuit is provided between the units for grasping the food allelbrowning lines are formed on each surface, but those on one surface areperpendicular or at different angle to those on the other. Thus, if thefood is turned over, a mesh or checkered browning efl'ect is formed oneach surface, and this is the reason for the perpendicular arrangementof the elements.

Another important property of the invention is that current flow onlythrough those bars that are engaged by the food. Thus, there is no wasteof current in idle elements, as in other electrical devices.

The provision of the plurality of bus bars connected to intermediatepoints between the ends of each line of elements distributes the currentmore uniformly than a smaller number of bars connected merely at theends of each line. In the latter arrangement the current would take thehalf of least resistance through and on the food, in close proximity tothe bars, and the remaining area of the food would be neglected. Thisobjection is avoided by the arrangement herein described Although specicembodiments' of the invention have been illustrated and described, itwill be understood that various alterations in the details ofconstruction may be made without departing from the scope of theinvention, as indicated by the appended claims.

What I claim is:

1. An electrical cooking apparatus comprising two units adapted toengage opposite surfaces of an article of food, each unit comprising apanel, parallel lines of conducting members thereon adapted to radiateheat at food-cooking temperatures, means electrically connectingalternate lines transversely at points intermediate their ends, dividingsaid lines into comparatively short lengths, means similarly connectingthe intermediate lines, said two means being adapted for connectionrespectively to opposite sides of a circuit, the lines on one panelbeing at an angle to those on the other panel.

2. An electrical cooking apparatus comprising two uni-ts adapted toengage opposite surfaces of an article of food, each unit comprising apanel, parallel lines -of conducting members thereon adapted to radiateheat at food-cooking temperatures, means electrically connectingalternate lines transversely, meansv similarly connecting theintermediate lines, said two means being adapted for connectionrespectively to opposite sides of a circuit, the lines on one panelbeing at an angle to those on the other panel.

3. An electrical cooking apparatus comprising two units adapted toengage opposite surfaces of an article of food, each unit comprising apanel, parallel lines of conducting members thereon adapted to radiateheat at food-cooking temperatures, means electrically connectingalternate lines transversely at points intermediate their ends, dividingsaid lines into comparatively short lengths, means similarly connectingthe intermediate lines, said two means being adapted for connectionrespectively to opposite sides of a circuit, the lines on one panelbeing at an angle to those on the other panel, said members beingsheathed in a conductive material resistant to repeated contact withfood under cooking temperature.

4. An electrical cooking apparatus comprising two units adapted toengage opposite surfaces of an article of food, each unit comprising apanel, parallel lines of conducting members thereon adapted to radiateheat at food-cooking temperatures, means electrically connectingaltercircuit, the lines on one panel being parallel to nate linestransversely at points intermediate those on the other, and means forpropelling food their ends, dividing said lines into comparativelybetween said units at a direction angular to said short` lengths, meanssimilarly connecting the lines.

intermediate lines, said two means being adapted 5 GLENN W. WATSON. forconnection respectively to opposite sides of a

